tbaeder created this revision.
tbaeder added reviewers: rsmith, aaron.ballman.
tbaeder requested review of this revision.
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As part of P1766R1
<http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1766r1.html>, allow
unnamed decls in `export{}` blocks.
I've adjusted the module-ts tests as well, but I am (generally) not sure
whether code for C++20 modules should affect the modules-ts cases. What's the
policy here?
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D117295
Files:
clang/include/clang/Basic/DiagnosticSemaKinds.td
clang/lib/Sema/SemaModule.cpp
clang/test/CXX/module/module.interface/p3.cpp
clang/test/Modules/cxx20-export.cpp
clang/test/SemaCXX/modules-ts.cppm
Index: clang/test/SemaCXX/modules-ts.cppm
===================================================================
--- clang/test/SemaCXX/modules-ts.cppm
+++ clang/test/SemaCXX/modules-ts.cppm
@@ -50,11 +50,8 @@
import foo;
export {} // expected-error {{export declaration cannot be empty}}
-export { // expected-note {{begins here}}
- ; // expected-warning {{ISO C++20 does not permit an empty declaration to appear in an export block}}
-}
-export { // expected-note {{begins here}}
- static_assert(true); // expected-warning {{ISO C++20 does not permit a static_assert declaration to appear in an export block}}
+export {
+ static_assert(true);
}
int use_b = b;
Index: clang/test/Modules/cxx20-export.cpp
===================================================================
--- /dev/null
+++ clang/test/Modules/cxx20-export.cpp
@@ -0,0 +1,22 @@
+
+// RUN: %clang_cc1 -std=c++20 -fmodules -verify %s
+export module testmodule;
+
+export static_assert(true); // expected-error {{static_assert declaration cannot be exported}}
+
+namespace A {};
+
+export {
+#define STR(x) constexpr char x[] = #x;
+ STR(foo);
+#undef STR
+
+ static_assert(true);
+
+ template <typename T> struct X { T t; };
+ template <typename T> X(T) -> X<T>;
+
+ ; // Empty declaration
+
+ using namespace A;
+}
Index: clang/test/CXX/module/module.interface/p3.cpp
===================================================================
--- clang/test/CXX/module/module.interface/p3.cpp
+++ clang/test/CXX/module/module.interface/p3.cpp
@@ -9,12 +9,6 @@
export static_assert(true); // expected-error {{static_assert declaration cannot be exported}}
export using namespace A; // expected-error {{ISO C++20 does not permit using directive to be exported}}
-export { // expected-note 3{{export block begins here}}
- ; // expected-error {{ISO C++20 does not permit an empty declaration to appear in an export block}}
- static_assert(true); // expected-error {{ISO C++20 does not permit a static_assert declaration to appear in an export block}}
- using namespace A; // expected-error {{ISO C++20 does not permit using directive to be exported}}
-}
-
export struct {}; // expected-error {{must be class member}} expected-error {{GNU extension}} expected-error {{does not declare anything}}
export struct {} struct_;
export union {}; // expected-error {{must be declared 'static'}} expected-error {{does not declare anything}}
Index: clang/lib/Sema/SemaModule.cpp
===================================================================
--- clang/lib/Sema/SemaModule.cpp
+++ clang/lib/Sema/SemaModule.cpp
@@ -615,13 +615,11 @@
return llvm::None;
}
-unsigned getUnnamedDeclDiag(UnnamedDeclKind UDK, bool InBlock) {
+static unsigned getUnnamedDeclDiag(UnnamedDeclKind UDK) {
switch (UDK) {
case UnnamedDeclKind::Empty:
case UnnamedDeclKind::StaticAssert:
- // Allow empty-declarations and static_asserts in an export block as an
- // extension.
- return InBlock ? diag::ext_export_no_name_block : diag::err_export_no_name;
+ return diag::err_export_no_name;
case UnnamedDeclKind::UsingDirective:
// Allow exporting using-directives as an extension.
@@ -640,8 +638,7 @@
static void diagExportedUnnamedDecl(Sema &S, UnnamedDeclKind UDK, Decl *D,
SourceLocation BlockStart) {
- S.Diag(D->getLocation(), getUnnamedDeclDiag(UDK, BlockStart.isValid()))
- << (unsigned)UDK;
+ S.Diag(D->getLocation(), getUnnamedDeclDiag(UDK)) << (unsigned)UDK;
if (BlockStart.isValid())
S.Diag(BlockStart, diag::note_export);
}
@@ -650,8 +647,10 @@
static bool checkExportedDecl(Sema &S, Decl *D, SourceLocation BlockStart) {
// C++2a [module.interface]p3:
// An exported declaration shall declare at least one name
- if (auto UDK = getUnnamedDeclKind(D))
- diagExportedUnnamedDecl(S, *UDK, D, BlockStart);
+ if (!BlockStart.isValid()) {
+ if (auto UDK = getUnnamedDeclKind(D))
+ diagExportedUnnamedDecl(S, *UDK, D, BlockStart);
+ }
// [...] shall not declare a name with internal linkage.
if (auto *ND = dyn_cast<NamedDecl>(D)) {
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -10971,9 +10971,6 @@
def err_export_within_anonymous_namespace : Error<
"export declaration appears within anonymous namespace">;
def note_anonymous_namespace : Note<"anonymous namespace begins here">;
-def ext_export_no_name_block : ExtWarn<
- "ISO C++20 does not permit %select{an empty|a static_assert}0 declaration "
- "to appear in an export block">, InGroup<ExportUnnamed>;
def ext_export_no_names : ExtWarn<
"ISO C++20 does not permit a declaration that does not introduce any names "
"to be exported">, InGroup<ExportUnnamed>;
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